


The Threesome

by morefishplease



Series: Comfy Fish Stories [66]
Category: Undertale (Video Game)
Genre: 69 (Sex Position), Creampie, Multi, Oral Sex, Threesome - F/F/M
Language: English
Status: Completed
Published: 2018-01-17
Updated: 2018-01-17
Packaged: 2019-03-06 03:00:15
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,238
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13402008
Author URL: https://archiveofourown.org/users/morefishplease/pseuds/morefishplease
Summary: Undyne and Alphys give you a threesome for your birthday.





	The Threesome

You glance up as Undyne pushes open the door, feel your breath catch in your throat as she slinks proudly around the corner, leaning up against the door, one arm out of view, the other perched on her bare hip. She’s wearing something very frilly and lacy and small and your eyes hardly know where to focus at once – her breasts, swelling against their flimsy containment, her thighs, poised just far enough that the tiny triangular gap between them is achingly apparent, the soft swell of her behind tantalizingly visible. You rake your eyes over her washboard abs, see her smile widen out of the corner of your eye as you continue drinking her in. There’s her calves, thick and muscular and sharp; she flexes them as you watch, and when your eyes flick up to hers she has on a smug smile, winks at you broadly, runs a hand over her stomach, down further, skirts it away at the last possible moment. She twirls slowly, sticks her ass out graceful, balancing on the balls of her feet in a quick, fluid motion that lets you see enough to flood even more blood toward your groin but not nearly as much as you want. You’ve set your book aside entirely, started to slide out of the covers, but she holds up a hand and you stop. As you manage to tear your eyes away, focus on her face for a moment, a strange bubble of lucidity floods up out of the roiling ocean of hot lust: Undyne is so beautiful, isn’t she? Isn’t she? Look at that face, those eyes, the way her fins are bobbing in excitement, the way she’s nibbling on her lip to try and keep from smiling but she can’t help herself. She loves this, you realize, she loves your reaction, the way you’re eating her up with your eyes, the way your cock is already outlined against your pants, straining against the tight fabric. She has such soft eyes, you think, when she isn’t trying to be cool. Her eyes are wide and murky, gold-flecked pools of amber trained on you like marksmen, and she blushes as your lustful smile turns into a dopey grin and she realizes what you must be thinking. She shrugs, the too-loose strap of her bra (if you can even call it that, it isn’t really big enough) slipping down her freckled shoulder. “Happy birthday,” she tells you and you wiggle your eyebrows at her.

“When do I get to unwrap my present?” you ask and she rolls her eyes, snickers. You can see her nipples puffing out through the sheer lace and your hardon throbs painfully, all too eager.

“Don’t you want to see all of your presents first?” Undyne asks, grinning broadly, teeth flashing, and you freeze.

“There’s more?”

“See for yourself,” she says, takes a few steps into the room, pulling Alphys in after her. The yellow lizard looks distinctly uncomfortable done up in such a skimpy outfit, you think as your eyes meander over her body. While Undyne has obviously gone to the effort of dressing up for you, Alphys looks as though she’s just shed her clothes, revealing her usual underwear, nothing fancy. Still, there is something distinctly erotic about her, you think as she tries half-heartedly to cover herself before Undyne grabs her hands, presses them down to her sides. The way her breasts spill out of her bra slightly coaxes another twitch from your hardon and though she may not have Undyne’s same thigh gap or washboard abs, she’s not nearly as frumpy naked as she looks when she’s wearing that big lab coat. You run your eyes over her chubby belly, lingering on the soft indent of her navel, let them wander down over her thick, stumpy legs, broad and sturdy. You notice she’s blushing hard, and her eyes keep flicking between your face and your hardon. She’s fiddling with her hands awkwardly and Undyne flicks her eyes over, nudges her in the ribs. “Spin for him,” she says, and Alphys does a reluctant little twirl, taking a few steps to do it. Your eyes linger on her ass, her panties stretched tight over her round behind, watch as her tail flicks in agitation. When she’s facing you again her blush has deepened and you stare at each other for another frozen moment before Undyne nudges her again, tells her to tell you happy birthday.

“H-happy birthday,” Alphys stutters, eyes still lingering on your groin. “Your –“ she starts to blurt but claps a hand over her mouth, stops herself, at least until Undyne pulls her hand away, pinches her belly lightly.

“Spill it,” she says, grin turning sharp, eyes narrowing, and Alphys covers her face.

“Your cock looks so big,” she says, mumbling past her hands, faint note of mortification audible in her voice. Undyne winks at you and the little predator gleam in her eye is back, you notice, her pupil has dilated enough to obscure the entire thing and a dull film like a shark’s has flooded through it. There is a faint light within, that’s all.

“Go ahead and get it out, then,” Undyne commands, pushing Alphys forwards, and you lean back, shift your hips over. Alphys climbs up onto the bed and you stare down at her cleavage unabashed, feeling a wash of satisfaction as Alphys bites her lip, avoids your eyes. She runs her hand over your cock, so lightly you can barely feel it through your pants and your boxers, and she jumps a little as Undyne clambers up next to her, leans her head down, stares at Alphys as Alphys bites her lip, pulls down your pants. You flop free and you don’t think you’ve ever been quite this hard. Alphys gasps, reaches out, grabs you tightly, holds you upright. Undyne is staring at your cock too, you notice, and as you watch she licks her lips, glances back at you, winks. “Put it in your mouth,” she says to Alphys, her stare still boring a hole through you, and Alphys starts to protest, starts to stammer something out, and Undyne, quick as lightning, has a hand on the back of Alphys’ head, clutching one of her fleshy horns as a handle, presses her up against you. Alphys gasps but she puts out her tiny pink tongue, licks you up your shaft slowly, a faint bud of warm pressure moving up until she poises over your head, gathers her strength – but not quick enough for Undyne, who forces her down onto your cock, and you let out a little noise as her head plunges down, down, down, until her tongue is resting lightly between your balls. She coughs, chokes, sputters a little, then swallows (the ribbed motion sending a little tingle of pleasure through you), lets out a wet gurgle, starts to bob her head up and down.

Undyne slips over, presses your head back against the pillows with a very aggressive kiss, even for Undyne, leaving a little pinprick of blood on your lip from where she bit just a little too hard. As she wiggles out of her bra and your eyes gravitate to her breasts, round and firm and thick, the nipples hard as diamonds, you notice as she presses them together, runs them up and down your chest, you realize that you can smell Undyne already and you wonder at how turned on she must be. She reaches over, slips a hand into Alphys’ bra and she lets out a surprised, aroused moan, wet and sloppy against your cock, and you didn’t think it was possible but you feel yourself getting harder. Undyne smirks, juts her chin toward Alphys, the lizard’s head still bobbing obediently up and down on you. “How is she?” Undyne asks, and you grin, give her a thumbs up as you take her nipple into your mouth, grin as she bites her lip, presses more of herself into you. “Fuck,” she breathes. “I want you to eat me out,” she says, pulling back suddenly, sliding her sodden panties down, turning around and lowering herself down on your face. As she does some of her fluids drip onto you and you close your eyes, fit your tongue against her burning slit like a puzzle-piece, tight and perfect, start to lick. Undyne lets out a rattling, growling moan, and you can feel her reaching forward, playing with Alphys’ breasts; Alphys lets out another little noise, increases her pace, slips a hand down and cradles your balls, and you thrust forward into her mouth, coaxing a surprised squeak out of her.

From there things get a little hazy. There is so much to do, after all. Three times while your cock is buried deep inside Alphys’ mouth, prodding forward into her throat each time she chokes down all the way, eager to feel your full length inside her, three times you feel yourself about to come, and you press Alphys back roughly, and before she can say anything, her eyes full of breathless confusion, Undyne surges forward, gathers Alphys into her arms, kisses her roughly, slipping a hand into her panties. They moan together, Undyne thrusting methodically against your face, too distracted with Alphys to do more than shudder, and you notice with some amusement that Alphys has started rubbing herself against your leg, leaving a wet trail up and down your thigh.

Undyne pushes Alphys off of you, squats over you, spears you into herself, ultraggressive, rides you with a swift rocking motion as Alphys watches, rubbing herself vigorously. You reach over, bat her fingers out of the way, and she spreads herself for you. You can feel her breathing quicken as you slip a finger into her moist slit, tight and wet and willing…

…at some point you end up pressing Alphys up against a wall, pounding into her while Undyne flattens herself against your back, hands on your hips, driving you forward. Alphys is crying tears of pleasure, letting out rhythmic, squeaking moans, and it is altogether too much for the little lizard as she practically convulses around your cock, the throes of her orgasm massaging you up and down as she shakes, grabs at you to keep her balance. When you look back Undyne is grinning…

…the same wide sharkgrin she gives while she is down on all fours, running her long, rough tongue over your cock. As you reach down, grab a rough handful of her hair she lets out a needy moan, reaches back and pulls Alphys into her, grinds the lizard into her groin, ignores Alphy’s mild squeal of shock…

…that she lets out when Undyne lunges, slips two fingers into her waiting slit. Alphys moans,  tries to squeeze her legs together. “N-not a-ga-ain,” she stutters. “He j-just made me c-come –“ she says, trying to press Undyne away, but Undyne pins her adroitly with her other arm, bobbing forward in a harsh rhythm as you pound away at her. “Just – ah! – lay back and enjoy it,” she hisses, and Alphys, utterly cowed, lays back, squeezes her breast, blushes harder. Undyne’s fingers are covered in a sticky web of Alphys’ cum and as she runs them over Alphys’ swollen clit the lizard shakes again, lets out a shrill scream…

…and Undyne covers her mouth, eyes still squeezed shut tight with pleasure, shocked that you coaxed that noise from her. She puts a hand on her stomach, grins as she feels you pressing against her, bulging her stomach out lightly, and as you reach down, run your thumb over her clit she twitches, reaches forward, caresses your face as she murmurs your name over and over again until her legs start to shake and she throws her head back in wordless ecstasy.

 

At the end of it all you press Alphys’ and Undyne’s heads together, cheek to cheek, and they eagerly lick at your throbbing cock. You feel like you’ve just ran a marathon, but you can’t quit now, not while the finish is in sight –

Alphys licks her way down to your balls, takes one into her mouth, and Undyne chuckles, squeezes the lizard’s breast, head bobbing roughly as she urges you with her eyes to come down her throat, not to waste a drop. It’s too much, it’s altogether too much, and as Alphys’ glazed, unfocused eyes emerge from beneath your cock and she nibbles at you lightly you twitch, groan, pour into Undyne for what seems like forever. You are still coming when she coughs, chokes, pulls away, and Alphys takes you into her mouth, greedy. You can feel her tongue running again and again in quick circles over your tender head and you blast the last spurt down her throat, collapse back onto the bed. Undyne wipes her gills, kisses Alphys, runs her tongue over the lizard’s teeth, feeling the last traces of your warm cum vanish as Alphys swallows, and Undyne punches her lightly.

 

▪ ▪ ▪

 

The next morning you wake you nestled between the two, healthy, radiant glow suffusing everything. As you stir Undyne’s eyes flick open and she gives you a sleepy little grin. “Happy birthday,” she repeats, kissing you on your cheeks, neck, nose, lips, and Alphys yawns, rolls over, kisses you and Undyne both on the cheek, wraps her arms around you and nestles back in to the warm cranny between your shoulder and the pillow.

**Author's Note:**

> A very straightforward story. I think the request was literally 'Undyne and Alphys giving you a threesome for your birthday' or something like that. So this is just straight up porn, with very little story or anything. Personally, I think it's quite erotic. 
> 
> This was written back when I had more of a stomach for writing porn, so naturally there's more of it here. Generally I believe that understatement is better than overdescription; if you leave a lot to your reader's imagination, they're going to come up with something better than you can. On the other hand, here I definitely don't do that, or at least not as much - there is a little bit when it gets all segmented towards the end. People had just really wanted something extra-hot so I tried my hand at writing a full sex scene. I think this is at just about the sweet spot for length and taste, I wouldn't want to write one much longer than this. And, to be honest, I'd started running out of ideas towards the end.


End file.
